The present invention relates to a headrest and a vehicle seat provided with the headrest. More particularly, it relates to a headrest capable of being made in a head support state in which the headrest is raised with respect to a seat back and in a storage state tilted from the head support state, and a vehicle seat provided with the headrest.
Generally, a headrest for protecting the passenger's head is mounted on the upper part of a seat back of a vehicle seat. Conventionally, there has been publicly known a configuration in which the lower part of a pillar of the headrest is attached to a transverse rod, which extends in the right and left direction in the seat back, so as to be rotatable in the front and rear direction, and the pillar is attached so as to be movable in the right and left direction, whereby the headrest is moved transversely and then is tilted to the rear to be stored (see Japanese Unexamined Utility Model Application Publication No. 7-11951, hereinafter, “JP '951”).
Also, there has been proposed a technique in which a headrest includes a pillar that has a transverse shaft part and is mounted on the upper part of a seat back; a headrest main body the lower side of which is rotatably provided in the transverse shaft part of the pillar; and a tilting mechanism incorporated in the headrest main body to tilt the headrest main body to the rear, and the tilting mechanism includes a headrest urging element or elements that urge the upper part of the headrest main body to the rear side; a lock plate that is provided in the transverse shaft part of the pillar and has a first locking part; a latch that is provided in the headrest main body and has a second locking part that lock to the first locking part of the lock plate; a latch urging element or elements that urge the latch so as to lock the second locking part to the first locking part of the lock plate; and an actuator that disengages the second locking part of the latch from the first locking part of the lock plate against the urging force of the latch urging element or elements (see Japanese Unexamined Patent Application Publication No. 2005-349915, hereinafter “JP '915”).
Furthermore, there has been proposed a technique in which in a tilting headrest in which a bracket can be moved to a folded position and to an erected position, a concave part is formed in a locking reciprocating member and a locking member, and the locking reciprocating member is made slidable to a locked position and to an unlocked position by a spring (see U.S. International Patent Publication WO2005/120894A1, hereinafter “WO '894”).
The publicly known example of JP '951 has a problem in that the headrest rotates to the rear greatly together with the pillar and therefore the displacement thereof is large, and also the headrest occupies a large space when being stored because the rotating support point of the headrest exists in the upper part of the seat back under the headrest.
That is to say, when the headrest is tilted to the rear, the whole of the headrest projects to the rear side. This example also has a problem in that a pillar movement groove must be formed in the upper part of the seat back, so that not only is the construction complicated but also the headrest cannot be used commonly for other seat backs.
The publicly known technique of JP '915 has high versatility because the tilting mechanism of the headrest can be accommodated entirely in the headrest main body. However, this technique has a problem in that a size of some degree must be secured in the front and rear direction, and the thinning of headrest is limited because the first locking part of the lock plate and the second locking part provided on the latch to be locked to the first locking part are used, and the lock plate and the latch are arranged in the tilt direction.
In the publicly known technique of WO '894, the concave part is formed in the locking reciprocating member and the locking member, and the locking reciprocating member is made slidable to a locked position and to an unlocked position by the spring. Since the locked position and the unlocked position are changed over by the two members of the locking reciprocating member and the locking member, a spring force for urging a bracket in the fold direction is applied directly to the locking reciprocating member and the locking member, so that in some cases, it is difficult for the reciprocating movement of the locking reciprocating member to be accomplished smoothly. Also, in the case where a plurality of locking members are present, one locking reciprocating member is made slidable to the locked position and the unlocked position with respect to all the locking members. Therefore, this technique has a disadvantage in that the locking reciprocating member becomes large, so that a higher load is applied to the locking reciprocating member.
Also, in any of the above-described publicly known techniques, in a condition where vibrations occur, for example, when the vehicle is running, consideration has not been given to abnormal sounds and noise caused by the headrest.